Alert archive / Virginia / Mesoscale Discussions in 2014

Mesoscale Discussion 1318

July 8, 20146 states

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2014, 4:42 PM EDT for 6 states. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Jul 8, 2014, 4:42 PM EDT (20:42 UTC)
Expired: Jul 8, 2014, 5:45 PM EDT
In force: 63 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 99 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Washington County, MD, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Ocean County, NJ, Salem County, NJ, Warren County, NJ, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Schuylkill County, PA, York County, PA, Albemarle County, VA, Arlington County, VA, Augusta County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Highland County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Morgan County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 36 km from the middle of the area, began a volume at 20:42 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.7 hours before the alert went out and 31 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 54 J/kg
Mixed-layer CIN: -214 J/kg
Mixed-layer LCL: 1698 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 8, 5:05 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	5 hr
Jul 8, 7:44 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle	61 min
Jul 8, 1:04 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Garrett, Washington	7 hr
Jul 8, 4:00 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	90 min
Jul 8, 5:39 PM EDT	Mesoscale Discussion	SPC	Bergen, Essex, Hudson, Morris, Passaic, Sussex	66 min
Jul 8, 6:27 PM EDT	Severe Thunderstorm Watch	SPC	Bergen, Essex, Hudson, Passaic, Union	6 hr
Jul 8, 8:58 AM EDT	Mesoscale Discussion	SPC	Mercer	62 min
Jul 8, 11:29 AM EDT	Mesoscale Discussion	SPC	Allegheny, Armstrong, Beaver, Blair, Bradford, Butler and 37 more	91 min
Jul 8, 4:02 PM EDT	Mesoscale Discussion	SPC	Buchanan, Dickenson, Lee, Russell, Scott, Washington and 3 more	88 min

Nearby

Mesoscale Discussions in Virginia, 2014 Mesoscale Discussions in Pennsylvania, 2014 Mesoscale Discussions in Maryland, 2014 Every mesoscale discussion in 2014

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.